Objective To evaluate the outcomes and their influencing factors of treatment of complex acetabular fractures by combined approaches. Methods From January 2000 to August 2006, 31 patients with complex acetabular fractures were operated on by combined ilioinguinal and Kocher-Langenheck ap-proaches. Of them, 28 patients, 19 males and 9 females, were followed up for an average of 31 (14 to 82) months. Their average age was 40 (20 to 75) years. Postoperative reduction quality and long-term radio-graphic results were evaluated according to the Matta radiological systems. The modified Merle d' Aubigne-Postel hip scoring system was used for the functional outcomes. The MOS SF-36 was used to evaluate the quality of life. Results Reduction was anatomical in 17 cases (60.7%), good in 9 cases (32.2%), and poor in 2 cases (7.1%) . Radiographic long-term results were excellent in 16 cases (57.2%), good in 7 cases (25 %), fair in 3 cases (10.7%) and poor in 2 cases (7.1%). Heterotopic ossification occurred in 18 patients (64. 3%), with Brooker Class Ⅰ in 8 (28.6%), Class Ⅱ in 7 (25.0%) and Class Ⅲ in 3 (10. 7%). Osteonecrosis of the femoral head occurred in 2 patients (7.1%). The mean Merle d' or poor. In comparison with local general people, the domains of general health, vitality, emotional role and mental health in patients with complex acetabular fractures treated by combined approaches were intact (P>0.05); however, the domains of physical function, physical role, body pain and social function had significantly lower scores(P<0.05) . Conclusions Indications for the combined approaches are limited to complex fracture patterns involved both columns, such as both column fractures, transverse and posterior wall fractures and T-type fractures, for which anatomical (or good) reduction or rigid internal fixation cannot be achieved by a single approach. The quality of reduction is a crucial and controllable prognostic factor. Key words: Acetabulum; Fracture; Fracture fixation, internal; Treatment outcome; Combined approaches